Corroding-pot.



A. J. MEIER.

GORRODING POT. APPLIIGATION FILED MAY 9, 190s.-,

Patented Dec. 8, 1908.

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- L57JZ7EZEB yww/rgw flisdflnz'n A. J. MEIER.

. GORRODING POT.

APPLICATION FILED MAY 9, 190a.

Patented Dec. 8, 1908.

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JlIl/EIIYUP: QLBEQIJFffi/E I HI'BAHUPIZE- ALBERT J. MEIER, OF ST. LOUIS, MISSOURI.

COBRODING-POT.

Specification of Letters Patent.

Patented Dec. 8, 1908.

Application filed May 9, 1908. Serial No. 431,917.

To all whom it may concern:

Be it known that I, ALBERT J. MEIER, a citizen of the United States, residing at the city of St. Louis, State of Missouri, have invented certain new and useful Improvements in Corroding-Pots, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to corroding-pots, such as are employed in the manufacture of white lead, and the essential feature of the invention is that the pot is made, in part at least, of lead, instead of being made of glass or earthenware, as heretofore.

The article commonly called white lead comprises a complex mixture of carbonate and hydroxid of lead, in somewhatvarying proportions, and is pre ared by treating metallic lead under sucli conditions, and bringing it into contact with such substances, {has the metal will be converted into white Most of the White lead made in this country is manufactured by the so called Dutch process, which process, so far as pertinent to this invention, may be briefly described as follows: The metallic lead from which white lead is to be made is usually formed in thin stri s or perforated disks, by the trade called uckles. These buckles are then placed in suitable pots, the buckles being provided with teats and arranged in a pile within each 0t, and, depending u on the shape of the uckle, sometimes in p es, with air-spaces between the buckles due to the presence of the teats, the lowest of said buckles being a short distance above the bottom of the pot. Acetic acid is then placed in the pot, the acid preferably extending so high as the lowest buckle. After the buckles and the acid have thus been placed in a great number of pots, the pots are arranged in the room or corroding-chamber in which the white lead is made. Said corroding-chamber must be constructed so that when the door is shut the chamber will be practically air-tight, in order that none of the heat or gases generated in said chamber can escape therefrom. In this corroding-chamber, the pots are arranged in tiers, each tier supporting the ones thereabove. The pots of the bottom tier are set upon spent tanbark, and surrounded with the same. A flooring of boards is then laid with the boards resting upon the tops of the pots in the bottom tier,

and upon this floor another layer of tanbark and tier of pots is supported. A second such floor is then placed upon the tops of the pots of the second tier, which second floor supports a third layer of tanbark, tier of pots, and so on, there being as many tiers as ermitted by the capacity of the cham er. When the chamber has thus been filled with pots, etc., the door of the chamber is closed and tightly sealed, and the chamber allowed to remain unopened and its contents untouched until the process is complete and the buckles largely converted into white lead.

.The tanbark in the chamber begins to decompose when the chamber is closed, and this decomposition evolves heat and generates steam and carbon dioxid and some other gases, all of'which are retained within the corroding chamber. It will be un== necessary to trace all the chemical changes subsequently occurring in the closed cham her, and it suffices to say that, at the end of a period of about one hundred and twenty days, the acetic acid and carbon dioxid, assisted by the heat evolved, will have converted the largest part of the metallic lead into white lead. The corroding-chamber is then opened, and the corroding pots removed. In each pot a quantity of white lead will be found, sometimes mixed with metallic lead. The corroding pots are then emptied, the white lead and the metallic lead therein contained are separated by screening, the white lead is packed for shipment, and the metallic lead is melted and recast into buckles and used again.

Prior to the Cpresent invention, the cor roding-pots use to hold the acid and the buckles have generally been made exclusively of earthenware (usually vitrified) or glass, such pots having been provided because it was regarded as absolutely essential that the pot should be unaffected by the acid and the gases which convert the metal into white lead. Owing to' the great weight which the pots in the lowest tiers must bear during the relatively long time required for the manufacture of the white lead, large numbers of the earthen or glass pots are broken. Careless workmen, in stacking the pots in the corroding-chamber and in removing them therefrom, break many more. As a result of the breakage occasioned by the foregoing causes, a very great loss is entailed upon the manufacturer, and these losses are an important factor in the cost of white lead. It has been proposed, also, to use pots made entirely of lead, but since such pots are totally consumed by the acid, the white lead formed becomes mixed with the tan bark and part of the white lead is lost. Since, by the destruction of the pots, the supports for the various floors are also destroyed (for each tier of pots supports the floor above) it is necessary to use some leaden pots and some earthen pots, it being impracticable to place only pots made entirely of lead in a corroding chamber.

Owing to the space occupied by the earth enware or glass pots, the capacity of the corroding-chamber is, as will hereinafter be seen, unnecessarily reduced. In the first place, such pots do not themselves corrode nor form white lead, and, in the second place, their walls are so much thicker than are the walls of the pots hereinafter described, that they waste space.

The essential feature of this invention is that the corroding-pot is made partly of'lead and partly of some metal or substance, such, for exam le, as enameled iron or porcelain, which will not unite with the acid and gases in the corroding-chamber. V

A leaden pot will not break, as an earthen or glass ot will, and thusthe large losses occasione by breakage are completely obviated. More important still is the fact that a leaden pot will itself be attacked by the acid and gases in the corroding-chamber, and converted into white lead, and the manufacturer is thereby enabled to produce a greater quantity of white lead in the same corrodingchamber than where earthen pots are used, since he thus subjects a greater quantity of metal to the action of the acid and gases in the corroding-chamber than where part of the room within the'chamber is taken up by earthen pots. Since white lead works are invariably located in cities, where ground is valuable, an important advantage over earthen pots arises from the use of leaden ones, for the manufacturer, by using leaden pots, adds greatly to the capacity of his plant, since he increases the quantity of white lead which can be manufactured in a certain corroding-chamber without the necessity of enlarging or in any manner altering the chamber itself. Finally, the use of leaden pots in place of earthen or glass pots,

tends to expedite the formation of the white lead, since the walls of the leaden pots will communicate to the interior of the pot the heat generated in the chamber, while an earthen or glass ot, being a non-conductor ofheat, tends to l eep the contents of the pot from becoming heated.

In the drawings forming art of this specification, in which like num ers of reference denote like parts whereverth'eyoccur, Figure 1 is a top plan view of the herein-deview.

' The drawings depict the referred form of the invention, but it shou d be understood that the shape of the pot can be altered as circumstances may render desirable.

The pot com rises the acid-cup l, in which the acetic aci is placed, which cup terminates in a shoulder 2 upon which the buckles of lead rest. The wall 3 of the pot above the shoulder 2 is made of lead, and is of approximately the same thickness as the uckles, so that the wall will dissolve at about the same rate as the buckles do under the action of the acid and the gases within the corroding-chamber. The wall 3 is provided with a plurality of perforations 4 of any desired size, location, and shape, through which perforations the gases contained within the corroding-chamber are adapted to circulate. Some of the perforations preferably extend from the top part wayto the shoulder 2 and other perforations from the shoulder part way to the top. A hoop 5 encircles the top and binds the wall together.

On either theinner or the outer side of the pot, beads 6 are formed, which beads extend vertically upward from the bottom of'the pot. The wall of the pot is so thin that it will be eaten away and converted into white lead, while the beads 6, being relatively thick, will be left standing and will uphold the upper tiers of pots. The cup 1 is so constructed that it will not be entirely destroyed by the action of the substances in the corroding chamber. This end is preferably secured by making the cup of an alloy of lead or of some metal other than lead, though the cup may be made entirely of lead, but so much thicker than the wall that the cup will be only partly eaten away, the greater part thereofremaining intact, serving to collect the white lead formed out of the buckles and the wall 3.

Preferably, the cup 1, wall 3, hoop 5, and beads 6 all comprise an integral formation especially so where all the parts are of lead. In case the cup 1 and heads 6 are of some substance other than lead they may be joined to the remaining parts of the pot in any suitable manner. The cup may be reinforced by ribs 7, if so desired, which ribs will facilitate removal from the mold or mandrel upon which the pot is formed.

Having thus described my said invention, what I claim and desire to secure by Letters- Patent is:

1. A corroding 0t comprising an acidcup, a leaden wall: and reinforcing means intermediate said cup and the top edge of said wall to strengthen said wall.

2. A corroding pot comprising an acidcup, a perforated leaden wall, and reinforcing means intermediate said cup and the top edge of said wall to strengthen said wall.

3. A corroding pot comprising an acidcup, a leaden wall, and a bead or beads to reinforce said wall.

4. A corroding pot comprising an acid-cup and a leaden wall, said leaden wall being thicker in some places than in others, the thicker portion being intermediate said cup and the top edge of said wall and being ad? ted to reinforce the remainder of the wa 5. A corroding pot comprising an acidcu and a perforated leaden wall, said leaden wal being thicker in some places than in others, the thicker portion being intermediate said cup and the top edge of said wall and being adapted to reinforce the remainder of the Wall.

6. A corroding ot comprising an acid cup, a leaden wall? reinforcing means for said Wall, and a hoop to bind said wall together.

7. A corroding pot comprising a wall which is adapted to be entirely destroyed by the action of the substances in the corroding chamber, and an acid-cup composed of such materials that said cup is indestructible by said substances.

8. A corroding pot comprising a wall which is adapted to be entirely destroyed by the action of the substances in the corroding chamber, a reinforcement for said wall, and an acid-cup, said cup and said reinforcement being composed of such materials as to be indestructible by said substances.

9. A corroding pot comprising an acidcup and a wall, said cu being composed of lead-alloy and said wal being composed of ead.

In testimony whereof I have. affixed my signature in presence of two witnesses.

ALBERT J. MEIER.

Witnesses EDNAJ. GooKEL, GLADYS WALTON. 

